Method and apparatus for implanting a knee prosthesis

ABSTRACT

A method for preparing a femur for receiving a prosthesis. The method includes the following: fixing a femoral trial component to the femur; coupling a reamer bushing relative to the femoral trial component; reaming a cavity into the femur using the reamer bushing as a guide; coupling at least one of a modular femoral box trial and a stem adapter relative to the femoral trial component; trialing the femoral trial component with the articulating surface of the femoral trial component; and performing the coupling of the reamer bushing, the reaming of the cavity, the coupling of the at least one of the modular femoral box trial and stem adapter, and the trialing of the femoral trial component all while the femoral trial component remains fixed to the distal femur.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/153,983 filed on Jun. 6, 2011, the entire disclosure of which isincorporated herein by reference

FIELD

The present disclosure relates generally to instruments for preparing atibia and femur for knee joint prostheses and more particularly toinstruments and related methods for using the instruments to prepare atibia and femur for receipt of a revision knee joint prosthesis.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

A knee joint prosthesis typically comprises a femoral component and atibial component. The femoral component and the tibial component can bedesigned to be surgically attached to the distal end of the femur andthe proximal end of a tibia, respectively. The femoral component canfurther be designed to cooperate with the tibial component in simulatingthe articulating motion of an anatomical knee joint. Such knee jointprostheses are generally referred to as primary knee prostheses.

Knee joint prostheses, in combination with ligaments and muscles,attempt to duplicate natural knee motion, as well as absorb and controlforces generated during the range of flexion. In some instances,however, it may be necessary to replace an existing prosthesis. Suchreplacement prostheses are generally referred to as revision kneeprostheses. Depending on the degree of damage or wear of the primaryknee prosthesis, knee tendons and ligaments, however, it may benecessary for a revision knee joint prosthesis to eliminate one or moreof these motions in order to provide adequate stability. In this regard,it may be desirable to provide a cruciate retaining (CR) revision knee,a fully constrained revision knee, a posterior stabilized (PS) revisionknee or a hinged revision knee for example. Furthermore, in someinstances, it may be necessary to account for bone loss in areasadjacent to such knee joint prostheses.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

A method for preparing a femur for receiving a prosthesis can includepositioning an intramedullary (IM) member in the femur. A femoral trialcomponent can be positioned onto a distal end of the femur. The femoraltrial component can have an attachment portion, an articulating surfaceand at least two cut surfaces thereon. A modular boss assembly can beattached to the attachment portion of the femoral trial component. Themodular boss assembly can have a boss stem that is configured tooperably connect to the IM member. A desired contact between the femoraltrial component and the distal femur can be confirmed based on theattaching. The femoral trial component can be fixed to the distal femurbased on the confirming. The modular boss assembly can be removed fromthe femoral trial component. A reamer bushing can be coupled relative tothe femoral trial component. A cavity can be reamed into the femur usingthe reamer bushing as a guide. At least one of a modular femoral boxtrial and a stem adapter can be coupled relative to the femoral trialcomponent. All of the steps including removing the modular bossassembly, coupling the reamer bushing, reaming the cavity and couplingthe modular femoral box trial and stem adapter are performed while thefemoral trial component remains fixed to the distal femur.

According to additional features, attaching the modular boss assemblycan include selecting the modular boss assembly from a plurality ofmodular boss assemblies each having a boss stem that extends along adistinct offset axis. Coupling the reamer bushing can comprise selectinga reamer bushing from a plurality of reamer bushings each having athroughbore that is offset a distance that corresponds to the offsetaxes of the boss stems. The reamer bushing can be selected based on theselected modular boss assembly. Attaching the modular boss assembly cancomprise locating a distal connection plate of the modular boss assemblyonto a recessed portion of the femoral trial component. Fasteners can beadvanced through passages defined through the distal connection plateand into threadable engagement with the femoral trial component and theattachment portion. According to other features, attaching the modularboss assembly can further comprise rotating the boss stem around a longaxis defined through the distal connection plate until a desiredorientation is attained relative to the IM member. Posterior stabilized(PS) box cuts can be prepared on the femur using the cut guide surfacesof the femoral trial component. Medial and/or lateral cuts can beprepared through a corresponding one of medial and lateral cut slotsdefined in the femoral trial component for receipt of a distal femoralaugment. According to one example, coupling the reamer bushing caninclude attaching a positioning ring to the attachment portion,inserting a reduced diameter portion of the reamer bushing into thepositioning ring, rotating the reamer bushing about its longitudinalaxis until the throughbore is aligned at a desired location, and fixingthe reamer bushing from further rotating.

According to still other features, attaching the positioning ring caninclude advancing fasteners through passages defined through thepositioning ring into threadable engagement with the femoral trialcomponent at the attachment portion. Fixing the reamer bushing fromfurther rotating can include advancing a peg associated with thepositioning ring into a corresponding locating bore defined in thereduced diameter portion of the reamer bushing. The modular femoral boxtrial can be coupled to the first attachment portion of the femoraltrial component. A stem adapter can be coupled to the modular femoralbox trial. The stem adapter can have an offset that corresponds to anoffset of the modular boss stem.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of various instruments used for preparing atibia for receipt of a tibial prosthesis according to various examplesof the present teachings;

FIG. 2 is a perspective view of a tibial spacer assembly according tothe present teachings;

FIG. 3 is a perspective view of one of the tibial spacers of the tibialspacer assembly in FIG. 2 located atop a resected proximal end of atibia to assist in determining a joint line;

FIG. 4 is a perspective view of an intramedullary (IM) reamer stopslidably coupled to a reamer;

FIG. 5 is a detailed perspective view of the reamer stop of FIG. 4;

FIG. 6 is a perspective view of the IM reamer stop engaging a proximaltibia while the reamer is preparing the IM canal of the tibia;

FIG. 7 is a perspective view of an IM tibial resection guide cooperatingwith the reamer shaft;

FIG. 8 is a perspective view of a resection block pinned to the tibiawhile a saw locates through one of the slots in the resection blockwhile a horizontal cut is made in the tibia for receipt of a medialtibial augment;

FIG. 9 is an anterior view of the tibia of FIG. 8 subsequent to thehorizontal cut and a vertical cut made on the proximal tibia for receiptof the medial tibial augment;

FIG. 10 is an anterior perspective view of the tibial template andoffset coin of the instruments illustrated in FIG. 1 shown with thetibial template resting atop the tibial plateau while the offset coin isrotated relative to a locating stem with a positioning tool to determinethe tibial offset;

FIG. 11 is an anterior perspective view of the tibial template andoffset coin subsequent to determining the preferred offset and removingof the positioning tool and with pins located through apertures of thetibial template to secure the tibial template to the proximal tibia;

FIG. 12 is a plan view of the tibial template and offset coin of FIG. 10and shown with a series of spring loaded spherical members locating intoa circumferential groove of the offset coin according to one example ofthe present teachings;

FIG. 13 is a cross-sectional view taken along lines 13-13 of FIG. 12;

FIG. 14 is a cross-sectional view taken along line 14-14 of FIG. 13 andshown with a stem adapter and locating stem coupled to the offset coin;

FIG. 15 is a cross-sectional view of the tibial template, stem adapterand locating stem of FIG. 14 and shown with the offset coin exploded;

FIG. 16 is an anterior perspective view of the tibial template pinned tothe proximal tibia in the desired location and with the offset coinbeing removed from the stem adapter with a removal tool;

FIG. 17 is an anterior perspective view of the tibial template shownwith an offset reamer bushing being aligned for receipt into a locatingbore of the tibial template;

FIG. 18 is a plan view of the offset reamer bushing positioned into thelocating bore at an orientation that corresponds with the radial offsetof the selected offset coin and rotational orientation that correspondsto the indicia noted on the offset coin;

FIG. 19 is a cross-sectional view taken along lines 19-19 of FIG. 18 andillustrating the spring loaded member locating into a circumferentialgroove of the offset reamer bushing;

FIG. 20 is an anterior perspective view of the tibial template shownwith an offset reamer of the instruments illustrated in FIG. 1 andlocated through the offset reamer bushing to prepare an offset cavityinto the tibia for accommodating an implant boss and an offset adapter;

FIG. 21 is an anterior view of the tibial template, offset reamerbushing and offset reamer of FIG. 20;

FIG. 22 is an anterior view of the tibia shown in FIG. 1 subsequent topreparation of the offset cavity and removal of the instruments and withan exemplary tibial component, offset adapter and tibial stem implantedwith respect to the prepared tibia;

FIG. 23 is an anterior perspective view of the tibial template shownwith a cruciate augment punch according to additional features;

FIG. 24 illustrates a tibia that has been prepared with the cruciateaugment punch of FIG. 23 for receipt of a winged augment and shown withthe winged augment coupled between a tibial tray and tibial stem in animplanted position;

FIG. 25 is an anterior perspective view of a tibial augment resectionblock coupled to an anterior portion of a trial tibial tray shown with atrial tibial bearing attached to the trial tibial tray;

FIG. 26 is an anterior perspective view of the tibial augment resectionblock alternatively coupled to the tibial template according to otherfeatures;

FIG. 27 is an anterior perspective view of the trial tibial tray andtrial tibial bearing of FIG. 25 and illustrated with a bearing removaltool located into a passage of the trial tibial bearing during couplingand decoupling of the trial tibial bearing to the trial tibial tray;

FIG. 28 is a cross-sectional view taken along lines 28-28 of FIG. 27 andshown with an actuator of the bearing removal tool being translated todisplace an engagement tab to decouple the trial tibial bearing from thetrial tibial tray;

FIG. 29 is an anterior perspective view of the trial tibial bearingbeing removed from the trial tibial tray with the bearing removal tool;

FIG. 30 is an anterior perspective view of the trial tibial tray shownwith an alternate tibial bearing according to additional features;

FIG. 31 is a perspective view of various instruments for preparing adistal femur according to the present teachings;

FIG. 32 is an anterior perspective view of a reamer stop positioned on aresected distal femur and shown with a reamer shaft extending into an IMcanal of the femur;

FIG. 33 is a perspective view of a femoral cut guide positioningassembly according to the present teachings;

FIG. 34 is an anterior perspective view of the femoral cut guidepositioning assembly located onto a distal femur and positioned relativeto the reamer shaft;

FIG. 35 is an anterior perspective view of a distal cut block of thefemoral cut guide positioning assembly pinned to a distal femur andshown with a saw preparing a horizontal cut for accommodating a medialaugment;

FIG. 36A is an anterior view of the femur of FIG. 35 and shownsubsequent to a vertical cut being made for receipt of a medial augment;

FIG. 36B is a perspective view of a set of femoral spacers according tothe present teachings;

FIG. 36C is an anterior view of the femur of FIG. 36A showing two of thefemoral spacers used to determine an augment thickness;

FIG. 36D is a perspective view of a series of resorbable augment trialspacers according to additional features;

FIG. 37 is a perspective view of a femoral cut block shown with afemoral offset coin assembly, stem adapter and locating stem accordingto the present teachings;

FIG. 38 is an anterior perspective view of the femoral cut block shownwith the positioning tool rotating an offset coin of the femoral offsetcoin assembly while the locating stem and stem adapter are positioned inthe IM canal of the femur;

FIG. 39 is an inferior view of the femoral cut block positioned on thedistal femur while the offset coin is rotated until the femoral cutblock slidably locates along the distal femur until a desired locationis attained;

FIG. 40 is an inferior view of the femoral cut block and offset coinassembly of FIG. 39 and shown with the femoral cut block positioned inthe desired location;

FIG. 41 is a cross-sectional view of the femoral cut block and offsetcoin assembly taken along lines 41-41 of FIG. 39;

FIG. 42 is a cross-sectional view of the femoral cut block and offsetcoin assembly taken along lines 42-42 of FIG. 40;

FIG. 43 is an anterior perspective view of the femoral cut block shownwith the removal tool removing the offset coin assembly, stem adapterand locating stem subsequent to pinning the femoral cut block at thedesired location;

FIG. 44 is an anterior perspective view of the femoral cut block shownwith a femoral cut block insert located into the locating bore of thefemoral cut block and with a saw preparing the distal cuts in the femur;

FIG. 45 is an anterior perspective view of a femoral cut-through trialpositioned onto the prepared distal femur;

FIG. 46 is an anterior perspective view of the femoral cut-through trialshown with the locating stem extending from the IM canal and with aseries of modular boss assemblies having various offsets that canselectively and alternatively connect to the locating stem;

FIG. 47 is a medial view of the tibia and femur shown with a modularboss assembly connected to the femoral cut-through trial and with aspacer positioned atop the tibial plateau to verify a desired jointline;

FIG. 48 is an anterior perspective view of the femur and shown with apositioning ring coupled to the femoral cut-through trial for receipt ofa corresponding femoral reamer bushing;

FIG. 49 is an inferior view of the femoral cut-through trial,positioning ring and selected femoral reamer bushings of FIG. 48;

FIG. 50 is a cross-sectional view of the positioning ring and reamerbushing taken along lines 50-50 of FIG. 49;

FIG. 51 is an anterior perspective view of the distal femur and shownwith a femoral offset reamer located through the femoral reamer bushingand preparing a cavity in the femur for receipt of a femoral offsetadapter;

FIG. 52 is an anterior view of the distal femur shown with the femoralcut-through trial, positioning ring, femoral reamer bushing and femoraloffset reamer of FIG. 51;

FIG. 53 is an anterior perspective view of the distal femur shown withthe femoral cut-through trial with various trial offset adapters andmodular boxes; and

FIG. 54 is an anterior view of the distal femur shown with an exemplaryfemoral component, offset adapter and femoral stem implanted into theprepared distal femur.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings. While the following discussion is directedtoward instruments and related methods for performing revision surgery,the same may be used as part of a primary knee replacement procedure.

With initial reference to FIG. 1, a system or kit of tools orinstruments for tibial preparation are shown and generally identified atreference numeral 10. In general, the kit of tools 10 can comprise atibial resection guide 12, a resection block 14, a reamer 16, and anintramedullary (IM) reamer stop 18. The kit of tools 10 can furthercomprise a tibial template 20, a series of positioning coins or offsetadaptors collectively referred to at reference numeral 22, a locatingstem 24, a stem adapter 26, a pair of reamers collectively referred toat reference numeral 28, a series of reamer sleeves collectivelyreferred to at reference numeral 30 and a pair of pins collectivelyreferred to at reference numeral 32. In general, the tibial resectionguide 12 and resection block 14 can be located relative to the reamer 16for preparing various horizontal cuts, such as medial and lateral cutson the proximal tibia as will be described herein. The positioning coins22, individually identified at reference numerals 22 a, 22 b, 22 c and22 d, each have bores 42 a, 42 b, 42 c and 42 d, respectively. Thepositioning coins 22 a, 22 b, 22 c and 22 d can be selectively andintraoperatively coupled to the stem adapter 26 and locating stem 24 androtated within a locating bore 36 of the tibial template 20 to determinea desired tibial offset as will be described.

The reamer sleeves 30, individually identified at reference numerals 30a, 30 b, 30 c and 30 d, can each have throughbores 44 a, 44 b, 44 c and44 d that have centers that correspond to, or are concentric with, therespective bores 42 a, 42 b, 42 c and 42 d of the positioning coins 22.The reamer sleeves 30 can also be positioned into the locating bore 36of the tibial template 20 at a rotational orientation that matches theorientation determined with the positioning coins 22. The reamer sleeves30 can then be used to guide the appropriate reamers 28 when preparing acavity in the proximal tibia for receipt of a tibial implant.

Turning now to FIGS. 2 and 3, a tibial spacer assembly 50 is shown. Inthe depicted example, tibial spacers 50 a, 50 b, 50 c, 50 d, 50 e, 50 f,50 g and 50 h are provided. The tibial spacer 50 a has a thickness of 10mm. According to the example shown, the tibial template 20 can also havea thickness of 10 mm such that the tibial spacer 50 a or the tibialtemplate 20 can alternatively be used when determining a desiredthickness of a tibial bearing. The remaining tibial spacers 50 b-50 heach have a thickness of 2 mm. The tibial spacer assembly 50 can bestacked, as needed, to achieve a desired height. The thickness of agiven stack of tibial spacers 50 a-50 h (or just the tibial spacer 50 aused alone) represents a desired thickness of a tibial bearing that willbe implanted at the proximal tibia. In the examples shown, the tibialspacer 50 b can be stacked onto the tibial spacer 50 a to collectivelydefine a thickness of 12 mm.

As can be appreciated, the tibial spacers 50 a-50 h can be sequentiallystacked to achieve additional increments of 2 mm. The tibial spacer 50 crepresents (e.g., the cumulative thickness of the tibial spacer 50 c,the tibial spacer 50 b and the tibial spacer 50 a) a thickness of 14 mm.The tibial spacer 50 d represents a thickness of 18 mm. The tibialspacer 50 f represents a thickness of 20 mm. The spacer 50 g representsa thickness of 22 mm. The spacer 50 h represents a thickness of 24 mm.In other embodiments, other thicknesses of the tibial spacer assembly 50and the individual spacers 50 a-50 h are contemplated. As shown, therespective spacers 50 a-50 h can each include a tibial plateau portion,collectively referred to by reference numeral 52, and a handle portion,collectively referred to by reference numeral 54. Each of the tibialspacers 50 a-50 h can be rotatably connected at terminal ends by way ofa fastener 56. The respective tibial spacers 50 a-50 h can eachpivotally rotate about the fastener 56 in order to isolate a desiredtibial spacer 50 a-50 h from the remainder of the spacers 50 a-50 h. Itcan be appreciated that while the respective tibial spacers 50 a-50 hare shown attached to each other through a fastener 56, they mayalternatively be unattached, separate pieces.

The tibial spacer assembly 50 can be used to find the joint line of atibia T using anatomical landmarks. More specifically, the tibialplateau portion 52 of a given tibial spacer 50 a-50 h can be placed atopthe tibial plateau of the tibia T or atop the resected proximal end ofthe tibia. In other words, the primary tibia is removed and the selectedspacer 50 a-50 h can be positioned on the previously resected proximaltibia. In the depicted embodiment, the spacers 50 a-50 h are universaland can accommodate a left or a right tibia. The appropriate joint linewill be confirmed when the proper thickness spacer 50 a-50 h is placedon the tibial plateau and presents a desired height (i.e., superiorlyfrom the tibial plateau) relative to anatomical landmarks. At this time,a thickness of optional, supplemental augments, such as those disclosedin currently pending and commonly owned U.S. patent application Ser. No.12/248,517, filed Oct. 9, 2008, incorporated by reference herein in itsentirety, can be determined. It can be appreciated that it may benecessary to provide supplemental augments on any combination of themedial and lateral sides of the tibia T. The joint line, or where thetibia T and femur F (FIG. 34) meet, is known once the desired thicknessof the identified spacer 50 a-50 h and the augmentation need isconfirmed and noted. In some examples, the host femur or femoral trialmay be located relative to the selected spacer 50 a, etc., to confirmthe thickness. The spacer assembly 50 is then removed from the tibia T.

With further reference now to FIGS. 4-6, additional features will bedescribed. Once the joint line has been determined relative to the tibiaT, the IM reamer stop 18 can be coupled to the reamer 16. The reamer 16can cooperate with the IM reamer stop 18 to prepare the IM canal of thetibia T. During use, the reamer 16 is able to ream a distance into theIM canal until the reamer stop 18 comes into contact with the proximaltibia.

The IM reamer stop 18 and the reamer 16 will now be described in greaterdetail. The IM reamer stop 18 can have a superior surface 60 and aninferior surface 62. The IM reamer stop 18 can define an opening 64 thatextends through the IM reamer stop 18 from the superior surface 60 tothe inferior surface 62. A finger support 66 can be supported on thesuperior surface 60 of the IM reamer stop 18. A button 68 can be coupledto a locating finger 70. The locating finger 70 can be movably fixed tothe finger support 66. In one example, the locating finger 70 can move(e.g., such as by depression of the button 68) along an axis that issubstantially transverse to an axis defined by the reamer 16. In oneexample, a biasing member 74, such as a spring in the depictedembodiment can bias the locating finger 70 into engagement with thereamer 16.

The reamer 16 can have a reamer shaft 78 that includes a plurality ofannular grooves, collectively referred to a reference numeral 80 formedthereon. As can be appreciated, the grooves 80 can provide a nestinglocation for the locating finger 70 to control the depth of reaming forthe reamer 16. According to one example, the groove 80 can be markedwith indicia (not specifically shown) that identify various depths ofreaming for the tibia T (as will become appreciated from the followingdiscussion, the reamer 16 and the IM reamer stop 18 can also be used forpreparation of the IM canal in the femur). In this regard, the grooves80 can also correspond to various depths of reaming in the femur aswell.

For exemplary purposes, the grooves 80 can correspond to 40 mm, 80 mm,200 mm and other depths of reaming to correspond to a desired stemlength. As can be appreciated, the various depths of cut can correspondto various lengths of tibial stems, such as a tibia stem 82 illustratedin FIG. 22. It can also be appreciated in some instances it may also benecessary to implant an offset adapter, such as the offset adapter 83illustrated in FIG. 22 for example. In those instances where an offsetadapter is needed in conjunction with a stem, the grooves 80 willcorrespond to different lengths of stem. For example, if a 40 mm offsetadapter will be used, the groove that corresponds to an 80 mm tibialstem will also correspond to a 40 mm tibial stem with a 40 mm tibialoffset adapter. Those skilled in the art can appreciate that thedimensions described herein are merely exemplary. In this regard,grooves can be provided in any combination of configurations along thereamer 16 for identifying a depth of reaming that can accommodate anycombination of stems and/or offset adapters as necessary.

With specific reference now to FIG. 6, use of the reamer 16 and reamerstop 18 relative to a tibia T will be described. In some examples,various reamers 16 having distinct diameters can be used until adequatecortical contact is achieved in the tibia T. Multiple IM reamer stops 18can be provided, each being operatively connected to a reamer 16 havinga distinct diameter. In this way, a surgeon, when switching to a reamerhaving a larger diameter, can simply remove the combination of reamer 16and IM reamer stop 18 and utilize another collective set of reamer andIM reamer stop. As can be appreciated, this can minimize the amount oftime that may be required to remove a reamer 16 from the opening 64 inan IM reamer stop 18 and replace it with a reamer having anotherdiameter.

Once the IM canal of the tibia has been sufficiently prepared, as shownin FIG. 6, the IM reamer stop 18 can be removed from the reamer 16. Thereamer 16 can remain in the IM canal. At this point, the reamer 16 canbe securely retained in a fixed position by the cortical bone of thetibia T and act as an IM guide. Next, as illustrated in FIG. 7, thetibial resection guide 12 can be slid over the reamer 16. The tibialresection guide 12 can generally comprise a body 84, an adjustment arm86, a block arm 88 and a stylus or finger 90. The body 84 can include aresection level adjustment knob 92. The adjustment arm 86 can include ahub 94 that has a passage 96 formed therethrough. The passage 96, asshown, can slidably receive the reamer shaft 78 of the reamer 16. Thefinger 90 can be used to engage the posterior tibia T. A coupler 100 canadjustably secure the adjustment arm 86 through a slot 102 formedthrough the body 84. The resection block 14 can then be secured to theblock arm 88. The resection block 14 can define a series of slots 106 ona medial and lateral side. In various embodiments, a trial stem (notshown) may be inserted into the IM canal in order to act as apositioning reference in place of the reamer 16.

The body 84 can be adjusted along the adjustment arm 86 to position theresection block 14 against the tibia T. The resection level adjustmentknob 92 can be rotated to place the resection block 14 at a desiredlevel (i.e., relative to a proximal surface of the tibia T). In otherwords, the resection block 14 can be moved inferiorly/superiorly on theanterior side of the tibia T until the desired location is attained.Once the desired location of the resection block 14 has been achieved,the resection block 14 can be fixed to the tibia T (such as by pins110). The remainder of the IM tibial resection guide 12 along with thereamer 16 can be removed. According to other examples, a medialresection guide 14 a and/or a lateral resection guide 14 b can be usedin place of the resection block 14.

With reference now to FIGS. 7-9, an exemplary sequence for preparing theproximal tibia for receipt of a 5 mm medial augment and a 10 mm lateralaugment will now be described. It can be appreciated that themedial/lateral cuts can be made to accommodate any tibial augment, suchas those disclosed in currently pending and commonly owned U.S. patentapplication Ser. No. 12/248,517, filed Oct. 9, 2008 which is expresslyincorporated herein by reference. The resection level of the tibialresection guide 12 can be set by rotating the resection level adjustmentknob 92 to the desired position. In one example, rotation of theresection level adjustment knob 92 can adjust the block arm 88 between adistance of zero and 8 mm along a longitudinal axis of the block arm 88,which moves the cutting slots 106 in the resection block 14 a certaindistance from the top of the stylus or finger 90 in the direction of thelongitudinal axis of the block arm 88. It can be appreciated that theresection level adjustment knob 92 can be configured to adjust the blockarm 88 to other distances. It can further be appreciated that othertibial resection guides may be used. Once the resection level is set, aclean-up cut can be made through the proximal most (or 0 mm) slot of theslots 106 on the medial side of the resection block 14. Similarly, a cutcan be made through the second proximal-most (or 5 mm) slot of the slots106 on the lateral side of the resection block 14. An exemplary tibia isshown in FIG. 9 after cutting, subsequent to using the resection block14. It will be appreciated that the depths of cut described above aremerely exemplary. Those skilled in the art will appreciate that a depthof cut will be made that is consistent with the joint line determined asdescribed above that can accommodate a thickness of a given bearing,such as bearing 114 illustrated in FIG. 22. Once the proximal tibia hasbeen prepared using the resection block 14, the resection block 14 canbe removed from the tibia T. Other methods for cutting the tibia foraccommodating an augment are discussed herein (FIGS. 34 and 35). In someexamples, the tibial spacers 50 (or portions thereof) can be used tofill the void left on the proximal tibia to provide a flat surface foraccommodating the tibial template 20. In other examples, shims or trialaugments (such as disclosed in currently pending and commonly owned U.S.patent application Ser. No. 12/248,517 identified above) may be used tofill the void.

With reference now to FIGS. 1 and 10-16, the offset position of theprepared IM canal 120 of the tibia T will be determined using a tibialoffset positioning assembly 122. The tibial offset positioning assembly122 can generally comprise the tibial template 20, the positioning coins22, the locating stem 24 and the stem adapter 26. Prior to describing anexemplary method for using the tibial offset positioning assembly 122,additional features of the tibial template 20, positioning coins 22,locating stem 24 and stem adapter 26 will be described in greaterdetail. The tibial template 20 can generally include a body 124 havingan anterior portion 126, a posterior portion 128, a medial portion 130and a lateral portion 132. In the particular example shown, the medialand lateral portions 130 and 132 are arbitrarily named as the tibialtemplate 20 can be interchangeably used for either a right or a leftknee. The tibial template 20 can further include a mark or notch 133formed thereon. The locating bore 36 can be formed through the body 124from a superior surface 134 to an inferior surface 136 (FIG. 1). Thebody 124 can define a pair of radial slot passages 138.

A ledge 140 can be formed on at least a partial circumference of thebody 124 at the locating bore 36. The ledge 140 can further include afirst plurality of interface teeth 142. The body 124 can also define aseries of lateral bores 144 a, 144 b and 144 c (FIG. 12) radiallyextending from a center of the bore 36. According to one example, thebores 144 a, 144 b and 144 c can be formed from an exterior surface 148of the body 124 to the locating bore 36. Each of the bores 144 a, 144 band 144 c can have a spring biased ball assembly 150 a, 150 b and 150 c,respectively therein. Each of the spring biased ball assemblies 150 a,15 b and 150 c can include a biasing member 152 a, 152 b and 152 c thatbias a ball 154 a, 154 b and 154 c in a direction toward the locatingbore 36 for cooperating with the respective positioning coins 22 as willbe described. According to one example, each of the bores 144 a, 144 band 144 c can include stops 158 a, 158 b and 158 c therein that capturethe respective springs 152 a, 152 b and 152 c. According to someexamples, the bores 144 a, 144 b and 144 c can be stepped, such that therespective stops 158 a, 158 b and 158 c can be advanced to a locationwhere the stepped bores transition to a reduced diameter. It is furtherappreciated that the bores 144 a, 144 b and 144 c have a diameter lessthan the balls 154 a, 154 b and 154 c near the locating bore 36 at aretaining wall (identified at reference 159 a, FIG. 13) to capture therespective balls 154 a, 154 b and 154 c in the body 124 of the tibialtemplate 20. Other configurations are contemplated. The anterior portion126 of the body 124 can include a pair of circumferential recesses 160.

The locating stem 24 can generally include a distal end 166 and aproximal end 168 (FIG. 14). The proximal end 168 can include a hub 170and a collar 172 formed thereon. The stem adapter 26 can generallyinclude a distal end 174 and a proximal end 176. The distal end 174 candefine a blind bore 178 therein. The proximal end 176 can include aprojection portion 180 (FIG. 15). A pair of circumferential grooves 182can be formed around the projection portion 180. As will be describedherein, the hub 170 of the locating stem 24 can be configured to locateinto the blind bore 178 of the stem adapter 26. Similarly, theprojection portion 180 of the stem adapter 26 can be configured to bereceived by a bore (such as the bore 42 c) of a positioning coin 22(such as the positioning coin 22 c)

With specific reference now to FIG. 1, the positioning coins 22 will bedescribed in greater detail. In general, the positioning coins 22 cangenerally provide a disc-like shape and each have a circumferentialgroove 188 formed therearound. Similarly, each of the positioning coins22 can include a pair of locating apertures 192. The locating apertures192 can each have a first diameter portion 192 a and a second diameterportion 192 b. The second diameter portion 192 b can have a diameterless than the first diameter portion 192 a for interfacing with aremoval tool (FIG. 16). Each of the positioning coins 22 b, 22 c and 22d can also include indicia 194 thereon. The positioning coins 22 caninclude a neutral positioning coin 22 a (zero offset), an offsetpositioning coin 22 b (2.5 mm offset), an offset positioning coin 22 c(5 mm offset) and an offset positioning coin 22 d (7.5 mm offset). Thepositioning coins 22 can each define the throughbores 42 a, 42 b, 42 cand 42 d, respectively that are offset a distance from a longitudinalaxis of the center of the positioning coins 22, collectively identifiedat reference numeral 200.

With reference now to FIGS. 14 and 15, according to one example, asurgeon can couple the locating stem 24 to the stem adapter 26 byinserting the hub 170 of the locating stem 24 into the blind bore 178 ofthe stem adapter 26. At this point, the surgeon can select one of thepositioning coins 22 that would appear to have a suitable offset forcooperating with the prepared IM canal 120 (FIG. 10). In the exampleshown in FIGS. 10-16, the surgeon has selected the positioning coin 22 c(having the 5 mm offset). It will be appreciated however that thesurgeon may need to intraoperatively switch between the positioningcoins 22 until the appropriate offset (recognizing that zero offset maybe used with the positioning coin 22 a) has been selected. According toone example, the projection portion 180 of the stem adapter 26 can beinserted into the bore 42 c of the positioning coin 22 c. In someexamples, an annular projection 184 provided in the bore 42 can createan interference fit with the groove 182 in the stem adapter 26. Ano-ring or other supplemental engaging member may also be positionedbetween the projection portion 180 and the bore 42 c. The positioningcoin 22 c can then be advanced into the locating bore 36 of the tibialtemplate 20 until the respective balls 154 a, 154 b and 154 c locateinto the circumferential groove 188 of the positioning coin 22 c. As canbe appreciated, the respective balls 154 a can initially translateagainst the bias of the springs 152 a, 152 b and 152 c, respectivelyuntil the groove 188 aligns for receipt of the respective balls 154 a,154 b and 154 c (FIG. 14). As can be appreciated, the respective balls154 a, 154 b and 154 c can be configured to ride along the groove 188 asthe positioning coin 22 c is rotated around the locating bore 36.

At this point, it is important to recognize that only the locating stem24 is fixed (or substantially fixed) relative to the tibia T. Thepositioning coin 22 c is able to rotate around its longitudinal axis 200causing the tibial template 20 to move around the proximal tibia (FIG.10). The positioning coin 22 c can be rotated (e.g., by the surgeon)around its longitudinal axis 200 with a positioning tool 210. Thepositioning tool 210 can generally include a handle 212 and a pair offork members 214. According to one example, the fork members 214 can beinserted into the first diameter portions 192 a of the respectivelocating apertures 192 of the positioning coin 22 c. The positioningcoin 22 c can be rotated (clockwise or counterclockwise) around the axis200 until a position is attained in which the body 124 achieves optimalcoverage over the proximal tibia T centered on cortical bone. Again, insome instances, the surgeon may need to swap out various positioningcoins (such as positioning the positioning coins 22 a, 22 b and 22 d) inorder to attain the best possible coverage of the proximal tibia. Oncethe desired position on the proximal tibia is verified, the tibialtemplate 20 can be fixed relative to the tibia T, such as by the pins 32(FIG. 11). At this point, the surgeon can make a note of the indicia 194relative to the mark 133 on the superior surface 134 of the tibialtemplate 20. This will correspond to the tibia offset position ordegrees offset. In some instances, it will be appreciated that no offsetwill be necessary (i.e., optimal coverage can be confirmed with the zerooffset positioning coin 22 a).

Once the tibial template 20 has been secured to the proximal tibia Twith the pins 32, the positioning coin 22 c can be removed from the stemadapter 26, such as with a removal tool 220. In one example, the removaltool 220 can have two fork portions 222 that have a first diameterportion 222 a and a second diameter portion 222 b. The second diameterportion 222 b can have a diameter less than the first diameter portion222 a. The first diameter portion 222 a can be advanced into the firstdiameter portion 192 a of apertures 192. The removal tool 220 can thenbe rotated around its longitudinal axis, such that the second diameterportions 222 b of the fork portions 222 locate into the second diameterportions 192 b of the apertures 192. In this position, the firstdiameter portions 222 a of the fork portions 222 can locate under anedge of the second diameter portion 192 b or a ledge 226 of the coin 22c to transfer a pulling force on the positioning coin 22 c. The stemadapter 26 and locating stem 24 can also be removed at this point.

With reference now to FIGS. 17-19, additional features will bedescribed. One reamer sleeve selected from the group of reamer sleevescollectively referenced by numeral 30 (FIG. 1) can then be located intothe locating bore 36 of the tibial template 20. The collective reamersleeves 30 can include the neutral reamer sleeve 30 a (0 mm offset orneutral offset), the offset reamer sleeve 30 b (2.5 mm offset), theoffset reamer sleeve 30 c (5 mm offset), and the offset reamer sleeve 30d (7.5 mm offset). As identified above, the reamer sleeves 30 can eachdefine a throughbore 44 a, 44 b, 44 c and 44 d, respectively. As can beappreciated, each offset corresponds to a radial offset from the centerof the sleeve or the longitudinal axis of the tibia T. Each of thereamer sleeves 30 can correspond to a respective positioning coin 22. Inthis regard, a surgeon can select an offset reamer sleeve 30 having asimilar offset as the positioning coin 22 identified above. The reamersleeves 30 can each define indicia 230 around its circumferential groove232 (FIG. 19). A second plurality of interference teeth 234 can beformed around a circumference of the reamer sleeves 30. The surgeon canthen rotationally align the indicia 230 of the reamer sleeve 30 c to themark 133 on the tibial template 20. It is important to recognize thatthe surgeon rotates (FIG. 17) the reamer sleeve 30 c (prior to locatingthe reamer sleeve 30 c into the locating bore 36 of the tibial template20) in order to align a common indicia 230 of the reamer sleeve 30 cwith the same indicia 194 that was determined by the positioning coin 22c (FIG. 12). Once the reamer sleeve 30 c has been rotated to the desiredorientation, the reamer sleeve 30 can be advanced into the locating bore36.

More specifically, the second plurality of interference teeth 234 canmeshingly align with the first plurality of interference teeth 142.Concurrently, the respective balls 154 a, 154 b and 154 c can locateinto the circumferential groove 232 of the reamer sleeve 30 c. As can beappreciated, the meshing engagement between the first plurality ofinterference teeth 142 and a second plurality of interference teeth 234can inhibit rotational movement of the reamer sleeve 30 c around itslongitudinal axis. Concurrently, the interaction of the respective balls154 a, 154 b and 154 c with the circumferential groove 232 of the reamersleeve 30 c can inhibit the reamer sleeve 30 c from coming out (axially)of the locating bore 36.

Turning now to FIGS. 20 and 21, once the offset reamer sleeve 30 c hasbeen advanced to the desired location, the offset reamer 28 a isinserted through the throughbore 44 c and an offset cavity 240 is reamedto accommodate an implant boss and an offset adapter (such as the boss242 and offset adapter 83 shown in FIG. 22). Notably, as illustrated inFIG. 21, the offset reamer sleeve 30 c has an upper plane 244 and alower plane 246 that are non-parallel. As can be appreciated, the seriesof offset reamer sleeves 30 can be provided having various upper andlower planes that diverge at various distinct angles. As can beappreciated, each offset reamer sleeve 30 can correspond to an angle ofreaming identified at reference 248 relative to the longitudinal axis249 of the tibia T that will accommodate the profile of any offsetadapter as needed (such as disclosed in U.S. patent application Ser. No.12/248,517, filed Oct. 9, 2008 identified above) as illustrated in FIG.22, the cavity 240 can accommodate the offset adapter 83.

In some examples, the neutral offset reamer sleeve 30 a can be used ininstances where an offset adapter is unnecessary. In such instances, thereamer 28 b (FIG. 1) can be used to ream an opening in the proximaltibia.

In examples where the tibia T must be prepared for receipt of a cruciateaugment 250 (FIG. 24), a cruciate augment punch 252 (FIG. 23) can bepassed through the locating bore 36 of the tibial template 20. Morespecifically, the punch 252 can have a winged plate with cutting teeth256 that can pass through the slot passages 138 formed on the tibialtemplate 20 while a surgeon grasps the ribbed handle portion 260. Thesurgeon can repeatedly axially drive the punch 252 through the locatingbore 36 creating the complementary passages in the proximal tibia toreceive the winged portions of the augment 250 as shown in FIG. 24.

With specific reference now to FIGS. 25-30, additional features of theinstant disclosure will be described. Once the tibia T has been reamedfor receipt of a tibial implant, trial tibial implants may be used todetermine optimal sizes for the replacement tibial component and bearing(such as tibial component 242 and bearing 114, shown in FIG. 22).Additionally, at this point, it may be desirable to prepare horizontalcuts in the tibia, such as on the lateral and/or medial tibia forreceipt of a tibial augment. In this regard, a tibial augment resectionblock locating tool 270 having a tibial augment resection block 272 canbe selectively and alternatively coupled to the tibial template 20 (FIG.26) or a trial tibial tray 276 (FIG. 25). The tibial augment resectionblock locating tool 270 can generally comprise a body portion 278 havinga distal end 280 and a proximal end 282. The distal end 280 cangenerally comprise a distal engaging disc 284. A handle 286 can bemounted for movement along a longitudinal axis 288 of the body 278 ofthe tool 270. According to one example, a user can initially locate thedistal engaging disc 284 into one of the circumferential recesses 160provided on the tibial template 20 (FIG. 26) or alternatively one of thecircumferential recesses 160′ (FIG. 25) provided on the trial tibialtray 276. The tibial augment resection block 272 can then be used tomake cuts in the tibia, such as medial cuts as shown in FIGS. 25 and 26and/or lateral cuts.

The trial tibial tray 276 will now be described in greater detail withreference to FIG. 29. The trial tibial tray 276 can generally comprise aposterior catch portion 290 that includes a posterior lip 292 and ananterior engagement portion 294 that includes a locking button 296. Thetrial tibial tray 276 can be configured to selectively andintraoperatively receive a trial tibial bearing 300. It can beappreciated that while one trial tibial bearing 300 is shown in thedrawings, a series of trial tibial bearings having various sizes andthicknesses will be provided. Similarly, a series of superiorlyextending members 302 a (FIG. 25), 302 b (FIGS. 27 and 29) and 302 c(FIG. 30) having various geometries according to one application can beconfigured to selectively couple to the trial tibial bearing 300 by wayof a fastener 304.

According to various features, the trial tibial bearing 300 can beselectively coupled to the trial tibial tray 276 by initially locating aposterior catch 310 (FIG. 28) of the trial tibial bearing 300 under theposterior lip 292 of the posterior catch 290 and subsequently advancingan anterior end 312 toward the trial tibial tray 276. A lock 316 caninitially and temporarily retract into the trial tibial tray 276 againstthe bias of a spring 320 that is retained within a bore 322 of the trialtibial tray 276 by a disc 324.

As illustrated in FIGS. 27 and 28, a bearing removal tool 330 can beprovided for selectively removing the trial tibial bearing 300 from thetrial tibial tray 276. In general, the bearing removal tool 330 caninclude a distal end 334 and a proximal end 336. An actuator 338 can beslidably mounted on a central body 340 of the bearing removal tool 330.The actuator 338 can have an engaging portion 342 formed thereon. Thedistal end 334 can generally comprise a distal tip 344 that can extendat an orthogonal angle relative to a longitudinal axis of the centralbody 340. The bearing removal tool 330 can be used to disconnect thetrial tibial bearing 300 from the trial tibial tray 276. In this regard,the distal tip 344 of the bearing removal tool 330 can be initiallyadvanced through a passage 350 (FIGS. 28 and 30) to depress the lock 360into the bias of the spring 320. Once the lock 316 has been sufficientlydepressed with the distal tip 320 (spring 320) of the bearing removaltool 330, a user can slidably advance the actuator 338 to provide agripping force onto the trial tibial bearing 300 at the passage 350. Thecentral body 340 can be fixed relative to the proximal end 336 while thetip 344 moves relative to the central body 340. Next, the user can liftthe trial tibial bearing 300 away from the trial tibial tray 276 (seeFIG. 29). At this point, the trial tibial tray and bearing combinationhaving the optimal fit with the tibia can be noted for correspondingwith the appropriate tibial implants. The trial tibial tray and bearingcan then be trialed with the distal femur F or femoral cut-through-trial570 (FIG. 45).

Turning now to FIG. 31, a system or kit of tools for femoral preparationare shown and generally identified at reference numeral 370. In general,the kit of tools 370 can comprise a femoral template 372, a series offemoral offset coin assemblies collectively referred to at referencenumeral 374, a femoral cut block insert 376, pins 378, the locating stem24 and the stem adapter 26. In general, femoral template 372 can be usedto determine an optimal position of a femoral component relative to anIM canal of the femur. The femoral template 372 can also act as a cutblock for guiding a cutting tool when preparing various cuts on a distalfemur once the desired location on the distal femur has been determined.In this regard, the femoral template 372 can generally comprise a body380 having an anterior portion 382, a posterior portion 384, a medialportion 385 and a lateral portion 386. In the particular example shown,the medial and lateral portions 385 and 386, respectively, arearbitrarily named as the femoral template 372 can be interchangeablyused for either a right or a left knee. The body 380 can further includean inferior surface 390 and a superior surface 392. A locating bore 394can be defined through the body 380 from the inferior surface 390 to thesuperior surface 392. In general, the locating bore 394 can define anoblong passage through the body 380. A shelf 396 can be formed on thesuperior surface 392 of the body 380 that generally projects into thelocating bore 394. The body 380 can also define an anterior cut slot400, an anterior chamfer cut slot 402, a first posterior cut slot 404, asecond posterior cut slot 406 and a posterior chamfer cut slot 408. Apair of pin passages 410 can be defined through the body 380 generallythrough the posterior portion 384. As will become appreciated, the pinpassages 410 can be configured to receive the pins 378 to fix thefemoral template 372 relative to the distal femur once the desiredposition has been attained.

The femoral offset coin assemblies 374 are individually identified atreference numerals 374 a, 374 b, 374 c and 374 d. Each femoral offsetcoin assembly 374 a, 374 b, 374 c and 374 d can comprise a femoral coinhousing 420 a, 420 b, 420 c and 420 d and a corresponding positioningcoin 422 a, 422 b, 422 c and 422 d. As will be described herein, thefemoral offset coin assemblies 374 can be selectively andintraoperatively secured within the locating bore 394 of the femoraltemplate 372 to determine a desired femoral offset. More specifically,the stem adapter 26 and locating stem 24 can be selectively coupledrelative to each of the positioning coins 422 a, 422 b, 422 c and 422 dwhile the associated femoral coin housing 420 a, 420 b, 420 c or 420 dis positioned into the locating bore 374 of the femoral template 372.

The femoral coin housings 420 a, 420 b, 420 c and 420 d can eachrespectively include a locating groove 424 a, 424 b, 424 c and 424 dthereon. The positioning coins 422 a, 422 b, 422 c and 422 d each haverespective bores 428 a, 428 b, 428 c and 428 d formed therein. Thelocation of the respective bores 428 a, 428 b, 428 c and 428 d cancorrespond to various offsets. Each of the bores 428 a, 428 b, 428 c and428 d are offset a distance relative to a longitudinal axis or center,collectively identified at reference numeral 430, of the respectivepositioning coins. In this regard, the femoral offset coin assemblies374 can include a zero offset (positioning coin 422 a), a 2.5 mm offset(positioning coin 422 b), a 5 mm offset (positioning coin 422 c) and a7.5 mm offset (positioning coin 422 d).

Each of the positioning coins 422 a, 422 b, 422 c and 422 d can includea pair of locating apertures 440. The locating apertures 440 can eachhave a first diameter portion 440 a and a second diameter portion 440 b.The second diameter portion 440 b can have a diameter that is less thanthe first diameter portion 440 a for interfacing with the removal tool220 (FIG. 43). Each of the positioning coins 422 b, 422 c and 422 d canhave an indicia 444 formed thereon. As will be described, the indicia444 can be referenced relative to a notch collectively identified atreference numeral 446 on the respective femoral coin housings 420 b, 420c and 420 d.

With reference now to FIG. 32, an exemplary method for preparing a femurF during revision surgery will be described. Again, it can beappreciated that in a revision surgery, it may be necessary to remove aprior implanted femoral component in any suitable manner. At the outset,the IM reamer stop 18 can be coupled to the reamer shaft 78 at thedesired location. The reamer 16 can cooperate with the IM reamer stop 18to prepare the IM canal of the femur F in a similar manner as describedabove with respect to preparation of the IM canal of the tibia (seeFIGS. 4-6). The reamer shaft 78 can be driven by a drive device (notspecifically shown) at a drive end. Also, as discussed above, thegrooves 80 can correspond to various depths of reaming into the femur F.As can be appreciated, the various depths of reaming can correspond tovarious lengths of femoral stems (such as femoral stem 450, FIG. 54).

As with the tibia described above, in some examples, it may be necessaryto implant an offset adapter (such as offset adapter 452, FIG. 54). Inthose examples where an offset adapter is needed in conjunction with astem, the grooves 80 will correspond to different lengths of stems. Forexample, if a 40 mm offset adapter will be used, the groove thatcorresponds to an 80 mm femoral stem (used alone) will also correspondto a 40 mm femoral stem that will be used in conjunction with a 40 mmfemoral offset adapter. Again, the grooves 80 can be provided in anycombination of configurations along the reamer shaft 78 for identifyinga depth of reaming that can accommodate any combination of stems and/oroffset adapters as needed. Furthermore, various reamers having distinctdiameters can be used until adequate cortical contact is achieved in thefemur F. Moreover, multiple IM reamer stops 18 can be provided, eachbeing operatively connected to a reamer 16 having a distinct diameter.

With reference now to FIG. 33, a distal revision cut assembly 460 willbe described. The distal revision cut assembly 460 can generallycomprise a distal revision block 462, a tower 464, a distal positioningplate 466, a first pair of pins 468, a second pair of pins 470 andmagnets 472. The distal revision block 462 can generally include aseries of cut slots 474, a plurality of pin passages 476 and a pair ofrecesses 478 for receiving the magnets 472. The tower 464 can generallyinclude a locating channel 480 and a pair of posts 482. The distalpositioning plate 466 can generally include a pair of bores 486 forselectively receiving the posts 482 of the tower 464. The distalpositioning plate 466 can further define a throughbore 488 foroperatively receiving the reamer shaft 78, as will be described. A pairof passages 490 can be defined in the distal positioning plate 466 forintraoperatively receiving the pins 470.

With specific reference now to FIG. 34, the distal revision cut assembly460 will be described according to one exemplary method of use.Initially, the throughbore 488 of the distal positioning plate 466 canbe advanced over the reamer shaft 78 until reaching a position againstthe distal femur. Next, the distal revision block 462 can be coupled tothe tower 464. In one example, the channel 480 of the tower 464 canlocate along the distal revision block 462, such that the magnets 472magnetically connect the tower 464 along the distal revision block 462.At this point, the posts 482 can locate through the bores 486 in thedistal positioning plate 466. It can be appreciated that the sequence ofassembly described with respect to FIG. 34 for the distal revision cutassembly 460 can be altered while still reaching the same result. Oncethe desired location has been attained, the distal positioning plate 466can be pinned to the distal femur using the second set of pins 470.Next, the first set of pins 468 can be located through the passages 476in a distal revision block 462 to pin the distal revision block 462 tothe distal femur. At this point, the reamer 16, distal positioning plate466 and tower 464 can be removed leaving only the distal revision block462 (see FIG. 35). Next, distal cuts can be made on the femur F usingany of the cut slots 474 defined through the distal revision block 462in order to make a distal resection or prepare for distal augments, ifnecessary (see FIG. 36A).

FIG. 36B illustrates exemplary femoral spacers 492. In the depictedexample, femoral spacers 492 a, 492 b, 492 c and 492 d are provided. Thefemoral spacer 492 a has a thickness of 10 mm. The remaining femoralspacers 492 b-492 d each have a thickness of 5 mm. The femoral spacerassembly 492 can be stacked, as needed, to achieve a desired height. Thethickness of a given stack of femoral spacers represents a desiredthickness of a femoral prosthetic component. For example, as shown onFIG. 36C, the femoral spacers 492 c and 492 d are stacked on a distalfemur F to determine a thickness of a medial femoral augment. Thespacers 492 can also be used to determine a thickness of a lateralfemoral augment.

The respective spacers 492 a-492 d can each include a distal femoralportion, collectively referred to by reference numeral 494, and a handleportion, collectively referred to by reference numeral 496. Each of thefemoral spacers 492 a-492 d can be rotatably connected at terminal endsby way of a fastener 498. The respective femoral spacers 492 a-492 d caneach pivotally rotate about a fastener 498 in order to isolate a desiredfemoral spacer 492 a-492 d from the remainder of spacers 492 a-492 d.Furthermore, the spacers 492 can be used to determine a joint line ofthe femur F using anatomical landmarks. Specifically, the distal femoralportion 494 of a given femoral spacer 492 a-492 d can be placed againstthe distal femur F. In one example, the primary femur can be removed andthe selected spacers 492 a-492 d can be positioned on the previouslyresected femur F. The spacers 492 a-492 d can be universal and canaccommodate a left of a right femur. The appropriate joint line can beconfirmed when the proper thickness spacer 492 a-492 d is placed on thedistal femur and presents a desired height (i.e. inferiorly from thedistal femur) relative to anatomical landmarks.

With reference to FIG. 36D, a series of augment trial spacers 499 a, 499b and 499 c are illustrated. In the example shown, the augment trialspacer 499 a can have a thickness of 5 mm, the augment trial spacer 499b can have a thickness of 10 mm and the augment trial spacer 499 c canhave a thickness of 15 mm. The thickness is identified as a dimension inthe superior/inferior direction as these augment trial spacers 499 a,499 b and 499 c can be configured to be located at a location on thedistal femur to fill the space of a removed femoral defect (i.e., suchas shown in FIG. 36A). The augment trial spacers are made ofbioresorbable material, such as Lactosorb®. Because the augment trialspacers 499 a, 499 b and 499 c are formed of bioresorbable material, ifneeded, a surgeon can simply cut or pierce through the augment trialspacers 499 a, 499 b or 499 c while preparing the bone. It can beappreciated that the augment trial spacers 499 a, 499 b and 499 c can beused in areas that are not only possible for engaging a saw blade butalso any of the pins, reamers or other cutting devices discussed herein.In this regard, a surgeon can make cuts, place pins and prepare the bonewithout worry for dulling the tools or creating debris, which the bodycannot easily handle. For example, if a saw blade or pin, such as anydisclosed herein, passes through the augment trial spacer and carriessome particles or small pieces of the augment trial spacer into thebone, the particles or small pieces will simply be absorbed into thebody without causing infection.

In some examples, some or all of the outside surfaces of the augmenttrial spacers 499 a, 499 b and 499 c can have a tacky or sticky surfacethat can facilitate gripping of the bone or adjacent instrument. Theaugment trial spacers 499 a, 499 b and 499 c can additionally includescore marks 500 a, 500 b and 500 c, respectively. The score marks canassist the surgeon in snapping or cutting off unneeded depth (in theanterior/posterior direction) of the augment trial spacers 499 a, 499 band 499 c. As shown in FIG. 38, the augment trial spacer 499 a is shownpositioned between the distal femur and femoral template 372. It can beappreciated that the augment trial spacers 499 a, 499 b and 499 c canadditionally or alternatively be used during preparation of the proximaltibia.

With reference now to FIGS. 31 and 37-42, the offset position of aprepared IM canal 501 of the femur F will be determined using a femoraloffset positioning assembly 502 (FIG. 37). The femoral offsetpositioning assembly 502 can generally comprise the femoral template372, the femoral offset coin assemblies 374 (FIG. 31), the locating stem24, the stem adapter 26 and the pair of pins 378. Prior to describing anexemplary method for using the femoral offset positioning assembly 502,additional features of the femoral template 372 will be described withreference to FIGS. 37, 41 and 42. The body 380 of the femoral template372 can have a pair of bores 510 a and 510 b, respectively formedtherein. According to one example, the bores 510 a and 510 b can beformed from an exterior surface 512 of the body 380 to the locating bore394. Both of the bores 510 a and 510 b can have a spring biased ballassembly 514 a and 514 b, respectively therein. Both of the springbiased ball assemblies 514 a and 514 b can include biasing members 516 aand 516 b that bias balls 518 a and 518 b, respectively in a directiontoward the locating bore 394 for selectively engaging the locatinggrooves (424 a, 424 b, 424 c and 424 d) of the respectively femoral coinhousings 420 a, 420 b, 420 c and 420 d as will be described. Accordingto one example, both of the bores 510 a and 510 b can include stops orset screws 520 a and 520 b therein that capture the respective biasingmembers 516 a and 516 b. According to some examples, the bores 510 a and510 b can be stepped, such that the respective stops 520 a and 520 b canbe advanced to a location where the stepped bores transition to areduced diameter. It can be further appreciated that the bores 510 a and510 b can have a diameter that is less than the balls 518 a and 518 bnear the locating bore 394 to capture the respective balls 518 a and 518b in the body 380 of the femoral template 372.

As described above, the locating stem 24 can be selectively coupled tothe stem adapter 26. In this regard, the hub 170 of the locating stem 24can be configured to locate into the blind bore 178 of the stem adapter26. Similarly, the projection portion 180 of the stem adapter 26 can beconfigured to be received by a bore (such as the bore 428 c) of apositioning coin, such as the positioning coin 422 c. In this regard,the surgeon can select one of the femoral offset coin assemblies 374that would appear to have a suitable offset for cooperating with theprepared IM canal 501 (FIG. 38). In the examples shown in FIGS. 37-43,the surgeon has selected the femoral offset coin assembly 474 c havingthe positioning coin 422 c that includes the 5 mm offset. It can beappreciated however that the surgeon may need to intraoperatively switchbetween the femoral offset coin assemblies 374 until the appropriateoffset (recognizing that zero offset may be used with the femoral offsetcoin assembly 374 a) has been selected. While not specifically shown, insome examples an annular projection (such as the annular projection 184identified in FIG. 15 of the positioning coin 22 c) can create aninterference fit with the groove 182 in the stem adapter 26. Again, ano-ring or other supplemental engaging member may also be positionedbetween the projection portion 180 and the bore 428 c. The femoraloffset coin assembly 474 c can then be advanced into the locating bore394 of the femoral template 372 until the respective balls 518 a and 518b locate into the groove 424 c of the femoral coin housing 420 c of thefemoral offset coin assembly 374 c. As can be appreciated, therespective balls 518 a and 518 b can initially translate against thebias of the springs 516 a and 516 b, respectively, until the groove 424c aligns for receipt of the respective balls 518 a and 518 b (see FIGS.41 and 42). It can also be appreciated that concurrently, the femoralcoin housing 420 c can rest atop the shelf 396 provided on the body 380at the locating bore 394.

At this point, it is important to recognize that only the locating stem24 is fixed (or substantially fixed) relative to the femur F. Thepositioning coin 422 c is able to rotate around its longitudinal centeraxis 430 within the femoral coin housing 420 c, causing the femoraltemplate 372 to move around the distal femur (see FIGS. 38-40). Thepositioning coin 422 c can be rotated (e.g., by the surgeon) around itslongitudinal axis 430 with the positioning tool 210. Similarly, asdescribed above with respect to the tibial offset positioning assembly122 described above, the fork members 214 can be inserted into the firstdiameter portions 440 a of the respective locating apertures 440 of thepositioning coin 422 c. The positioning coin 422 c can be rotated aroundthe axis 430 until a position (degree and/or offset) is attained inwhich the body 380 achieves optimal coverage or placed over corticalbone of the distal femur F. Again, in some instances, the surgeon mayneed to swap out various femoral offset coin assemblies 374 in order toattain the best possible coverage of the distal femur.

The femoral template 372 can also be used to verify joint space of theknee prior to making the distal cuts. In one example, the femoraltemplate 372 can have a thickness of 9 mm. The femoral template 372 canbe positioned on the distal femur while the tibial template 20 ispositioned on the proximal tibia. The joint space can be observed withthe knee in flexion to determine the optimal position of the femoraltemplate 372. The tibial spacers 50 (FIGS. 2 and 3) may also be used toaccount for additional space. Additionally, the femoral spacers 492 maybe used. In some examples, the tibial and/or femoral spacers 50, 492 canbe placed directly against the respective bones (i.e., without either ofthe tibial template 20 or femoral template 372). Because the system ofthe present teachings allows the surgeon to adjust the offset positionof the femoral template 372, a surgeon can open and close the flexionspace by moving the femoral template 372 around the distal femur usingthe tibial and/or femoral spacers as needed and observing the flexionspace in real time.

Once the desired position on the distal femur is verified, the femoraltemplate 372 can be fixed relative to the femur F, such as by the pins378 (FIG. 43). At this point, the surgeon can make a note of the indicia444 relative to the mark or notch 446 on the femoral coin housing 420 c.This will correspond to the femoral offset position. Again, in someinstances, it can be appreciated that no offset may be necessary (i.e.,optimal coverage can be confirmed with the femoral offset coin assembly374 a).

Turning now to FIG. 43, once the femoral template 372 has been securedto the distal femur F with the pins 378, the femoral offset coinassembly 374 c can be removed from the stem adapter 26, such as with theremoval tool 220. Similarly, with the tibial offset positioning assembly122 described above, the first diameter portion 222 a of the forkportion 222 can be advanced into the first diameter portion 440 a of theapertures 440. The removal tool 220 can then rotated around itslongitudinal axis, such that the second diameter portions 222 b of thefork portions 222 locate into the second diameter portions 440 b of theapertures 440. In this position, the first diameter portions 222 a ofthe fork portions 222 can locate under an edge of the second diameterportions 440 b a ledge 530 of the positioning coin 422 c to transfer apulling force onto the positioning coin 422 c. The stem adapter 26 andthe locating stem 24 can also be removed at this point.

Turning now to FIG. 44, once the femoral template 372 has been securelypinned to the distal femur and the femoral offset coin assembly 374 c isremoved from the locating bore 394, the femoral cut block insert 376 canbe inserted into the locating bore 394. At this point, the surgeon canmake the respective cuts on the distal femur using a cutting instrument534. More specifically, the surgeon can use the anterior cut slot 400,the anterior chamfer cut slot 402, the first posterior cut slot 404, thesecond posterior cut slot 406 and the posterior chamfer cut slot 408 asguides for the cutting instrument 534. In this regard, the femoraltemplate 372 can be utilized to not only assist in determining anoptimal femoral offset to achieve a desired coverage on a distal femur,but also be used as a cutting block to guide the cutting instrument 534when making the distal cuts on the femur F. Furthermore, the femoraltemplate 372 can be used as a spacer when verifying a joint line. In oneexample, the femoral template 372 can have a thickness of 10 mm.

Once the anterior cut, posterior cut and anterior and posterior chamfercuts have been made on the distal femur, the femoral template 372 andfemoral cut block insert 376 can be removed from the distal femur. Atthis point, a femoral cut-through-trial 570 can be positioned on theprepared distal femur F (FIG. 45). The femoral cut-through-trial 570 canbe used for both femoral trialing and as a guide for cutting portions ofthe femur F for receipt of femoral augments as will be described.According to one advantage of the present teachings, the femoralcut-through-trial 570 can remain fixed to the distal femur F once thedesired coverage and offset (if necessary) has been determined. Thefemoral cut-through-trial 570 can be used as a trial and includes arepresentative articulating surface 572 and a bone engaging surface 574.

The bone engaging surface 574 can be collectively formed by an anteriorbone engaging surface 576, an anterior chamfer bone engaging surface578, a distal bone engaging surface 580, a posterior chamfer boneengaging surface 582 and a posterior bone engaging surface 584. A seriesof bores 586 can be formed through the femoral cut-through-trial 570 forreceiving pins (588, FIG. 46) to fix the femoral cut-though-trial 570once the desired position has been attained on the distal femur. A pairof recessed flare portions 590 can be formed into the articulatingsurface 572. A threaded bore 592 can be provided at each of the recessedflare portions 590, respectively. A first and second series of medialcut slots 600 and 602 can be formed through the femoralcut-through-trial 570. A first and second series of lateral cut slots604 and 606 can be formed through the femoral cut-through-trial 570. Thefirst series of medial cut slots 600 can be used to guide the cuttinginstrument 534 for preparing medial cuts on the distal femur at alocation generally parallel to the distal bone engaging surface 580.

The first series of lateral cut slots 604 can be used to guide thecutting instrument 534 for preparing lateral cuts on the distal femur ata location generally parallel to the distal bone engaging surface 580.As can be appreciated, the first series of medial and lateral cut slots600 and 604 may be used if it is desired to remove portions of distal,medial and/or lateral femoral bone and replace the removed bone withdistal femoral augments. Similarly, the second series of medial andlateral cut slots 602 and 606 can be used to guide a cutting instrumentfor cutting posterior portions of the distal femur in a location that isgenerally parallel to the posterior bone engaging surface 584 of thefemoral cut-through-trial 570. In this regard, it may be desirable toremove portions of the medial and/or lateral posterior femur and replacethat area with posterior augments that attach to a femoral component.

With reference now to FIG. 46, a series of modular boss assemblies 610are shown for selectively and alternatively cooperating with thelocating stem 24 and the femoral cut-through-trial 570. In general, theseries of modular boss assemblies are identified individually atreference numerals 610 a, 610 b, 610 c and 610 d. The series of modularboss assemblies 610 can correspond with the femoral offset coinassemblies 374. In this regard, the modular boss assembly 610 a can havea boss stem 612 a that corresponds to a zero offset. The modular bossassembly 610 b can have a stem 612 b that corresponds to a 2.5 mmoffset. The modular boss assembly 610 c has a boss stem 612 c thatcorresponds to a 5 mm offset. The modular boss assembly 610 d has a bossstem 612 d that corresponds to a 7.5 mm offset.

The modular boss assembly 610 b can have an intermediate offset body 614b. The modular boss assembly 610 c can have an intermediate offset body614 c. The modular boss assembly 610 d can have an intermediate offsetbody 614 d. The modular boss assemblies 610 a, 610 b, 610 c and 610 dcan each comprise a distal connection plate 618 a, 618 b, 618 c and 618d defining a central aperture 620 a, 620 b, 620 c and 620 d forreceiving a connector, such as a connector 623 shown on the modular bossassembly 610 c. The distal connection plates 618 a, 618 b, 618 c and 618d can each include a pair of passages 624 a, 624 b, 624 c and 624 d thatare configured to receive fasteners 626 a, 626 b, 626 c and 626 d,respectively. The intermediate offset body 614 b of the modular bossassembly 610 b can interconnect the stem 612 b with the connector 622 b.The intermediate offset body 614 c of the modular boss assembly 610 ccan interconnect the stem 612 c with the connector 622 c. Theintermediate offset body 614 d of the modular boss assembly 610 d caninterconnect the stem 612 d with the connector 622 d. The intermediateoffset bodies 614 b, 614 c and 614 d can have a proximal connecting end630 b, 630 c and 630 d, respectively. The intermediate offset bodies 614b, 614 c and 614 d can also include a distal connecting end 632 b, 632 cand 632 d, respectively. Each of the proximal connecting ends 630 b, 630c and 630 d include a first plurality of interconnecting teeth 634 bthat selectively interlock with a second plurality of teeth 636 b on thestem 612 b. The first plurality of interconnecting teeth 634 b, 634 cand 634 d of the intermediate offset bodies 614 b, 614 c and 614 d caneach be rotated around the second plurality of interconnecting teeth 634b, 634 c and 634 d in the respective stems.

The distal connecting ends 632 b, 632 c and 632 d all include a thirdplurality of interconnecting teeth 640 b, 640 c and 640 d thatselectively engage a fourth plurality of interlocking teeth 642 b, 642 cand 642 d provided on the connectors 622 b, 622 c and 622 d,respectively. The third plurality of interconnecting teeth 640 b, 640 cand 640 d of the intermediate offset bodies 614 b, 614 c can each berotated around the fourth plurality of interconnecting teeth 640 b, 640c and 640 d on the connectors 622 b, 622 c and 622 d. As can beappreciated, the intermediate offset bodies 614 b, 614 c and 614 d caneach rotate around a longitudinal axis 650 collectively defined througheach of the distal connection plates 618 a, 618 b, 618 c and 618 d inorder to position the respective stems 612 b, 612 c or 612 d in arotational orientation (or at the selected rotation angle or degree)that will align with the IM canal of the femur. Once the desiredposition on the distal femur F has been attained, the femoralcut-through-trial 570 can be fixed to the distal femur F with the pins588. While only two pins 588 are shown, additional pins and/or pinslocated through other bores 586 may be used.

Turning now to FIG. 47, additional features of the present teachingswill be further described. With the femoral cut-through-trial 570secured to the distal femur and with the modular boss assembly 610 cattached at the recessed flare portion 590, the joint line 652 withrespect to the tibia T can be visualized using one of the tibialspacers, such as the tibial spacer 50 a. In this regard, the joint lineis represented by the tibial plateau portion 52 of the tibial spacer 50a, which is determined based on anatomical landmarks. At this time, thedistal augmentation needs for the tibia T and femur F can be determined.Moreover, a thickness of a tibial bearing can be verified.

With reference now to FIGS. 48-52, reaming of the femur to accommodate afemoral offset adapter (such as the offset adapter 452, FIG. 54) will bedescribed. A femoral offset reaming assembly 656 can include apositioning ring 658 and a series of reamer bushings, collectivelyreferred to at reference numeral 660. The reamer bushings 660 caninclude a neutral reamer bushing 660 a (0 mm offset or “neutraloffset”), an offset reamer bushing 660 b (2.5 mm offset), an offsetreamer bushing 660 c (5 mm offset) and an offset reamer bushing 660 d(7.5 mm offset). Indicia marks 664 are collectively formed around all ofthe reamer bushings 660. Similarly, a plurality of locating bores 668can be formed around a reduced diameter portion 670 of each of thereamer bushings 660. Offset bores 672 a, 672 b, 672 c and 672 d can beformed through each of the reamer bushings 660, respectively. The offsetbores 672 a, 672 b, 672 c and 672 d can be all formed through therespective reamer bushings 660 at an offset location relative to alongitudinal axis collectively identified at reference numeral 674 ofthe reamer bushings 660. It can be appreciated that the offset bore 672a of the reamer bushing 660 a can have a zero offset relative to thelongitudinal or center axis 674.

The positioning ring 658 will now be described in greater detail. Thepositioning ring 658 can generally provide a ring-shaped body 680 thatdefines an opening 682 therein. A pair of locating portions 686 can haveapertures 688 for receiving fasteners 690 that can selectivelythreadably locate into the threaded bores 592 on the femoralcut-through-trial 570. A locating peg 694 can extend from a pole handle696 that extends out of a neck 698 of the ring-like body 680. As will bedescribed, the peg 694 can selectively locate into one of the locatingbores 668 once the desired indicia 664 aligns with a mark 700 on thepositioning ring 658 to correspond with the noted indicia 444 that alignwith the notch 446 of the selected offset coin assembly 374 above.

Once the corresponding reamer bushing 660 has been selected that has anoffset that matches an offset identified from the selected offset coinassembly 374, the reamer bushing (such as the reamer bushing 672 cidentified in FIG. 48) can be located into the opening 682 of thepositioning ring 658. Next, the pole handle 696 can be pulled away fromthe ring-like body 680 and the reamer bushing 660 c can be rotatedaround the central axis to align the corresponding indicia 664 with themark 700 on the positioning ring 658 that corresponds with the notedindicia 440 and notch 446 determined above. At this point, the polehandle 696 can be pushed inwardly toward the ring-like body 680, suchthat the peg 694 securely locates into one of the locating bores 668 topreclude further rotation of the reamer bushing 660 c around the centralaxis 674.

At this point, a femoral offset reamer 710 can be located into theoffset bore 672 c and the offset cavity can be reamed. As shown in FIG.52, the offset reamer bushing 660 c has a first plane 714 and a secondplane 716 that are non-parallel. As can be appreciated, the series ofreamer bushings 660 can be provided having various first and secondplanes that diverge at various distinct angles relative to thelongitudinal axis of the femur F. As can be appreciated, each reamerbushing 660 can correspond to an angle of reaming that will accommodatethe profile of any given offset adapter (such as the adapter 452, FIG.54). In some examples, the neutral reamer bushing 660 a can be used ininstances where an offset adapter is unnecessary. It can be appreciatedthat the femoral offset reamer 710 can also ream an opening in thedistal femur that will accommodate a femoral implant boss 720 (FIG. 54).

With reference now to FIG. 53, femoral trial components 730 can be usedto cooperate with the femoral cut-through-trial 570 to trial theprepared distal femur. Again, the femoral cut-through-trial 570 remainsfixed to the distal femur F. Prior to using the femoral trial components730, a surgeon can cut a box opening into the distal femur with acutting instrument 731 using the femoral cut-through-trial 570 as areference.

The femoral trial component 730 can generally include a first modularbox 732, a second modular box 734, a first trial offset adapter 736, asecond trial offset adapter 738 and a third trial offset adapter 740.The first modular box 732 can be specific to a right femur while thesecond modular box 734 can be specific to a left femur. Each of themodular boxes 732 and 734 can include wing portions 780 that havepassages 782 that receive fasteners 784. The fasteners 784 can beconfigured to threadably mate with the threaded bores 592 in the femoralcut-through-trial 570. The first trial offset adapter 736 can have a 2.5mm offset, the second trial offset adapter 738 can have a 5 mm offset,and the third trial offset adapter 740 can have a 7.5 mm offset. As canbe appreciated, each of the offsets can correspond with the positioningcoins 422 and offset reamer bushings 660. Each of the trial offsetadapters 736, 738 and 740 can have a threaded boss portion 790 that canthreadably mate with a corresponding threaded bore 792 provided in eachof the modular boxes 732 and 734, respectively. A distal augment spacer794, and/or a posterior augment spacer 796 can be also used during thetrial sequence. In one example, the augment spacers 794 and/or 796 canbe magnetically coupled to the femoral cut-through-trial 570, such aswith a magnet 798. The femur F can then be trialed. In one example, thefemoral trial component 730 can be articulated through flexion andextension such that the articulating surface 572 rotates against thetrial tibial bearing 300 (FIG. 30). Once the femoral trialing sequencehas identified a suitable femoral component, offset adapter and femoralstem, a surgeon can input and implant a femoral component 800, theoffset adapter 452 and a femoral stem 450 as shown in FIG. 54.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A method for preparing a femur for receiving aprosthesis, the method comprising: positioning an intramedullary (IM)member in the femur; positioning a femoral trial component onto a distalend of the femur, the femoral trial component having an attachmentportion, an articulating surface and at least two cut guide surfacesthereon; fixing the femoral trial component to the distal femur;coupling a reamer bushing relative to the femoral trial component;reaming a cavity into the femur using the reamer bushing as a guide;coupling at least one of a modular femoral box trial and a stem adapterrelative to the femoral trial component; and trialing the femoral trialcomponent with the articulating surface of the femoral trial componentby rotating the articulating surface against an opposing bearingsurface; wherein coupling the reamer bushing, reaming the cavity,coupling at least one of the modular femoral box trial and stem adapterand trialing the femoral trial component are all performed while thefemoral trial component remains fixed to the distal femur.
 2. The methodof claim 1, wherein coupling the reamer bushing comprises: selecting areamer bushing from a plurality of reamer bushings, wherein at leastsome of the plurality of reamer bushings have an offset throughbore. 3.The method of claim 1, further comprising: preparing PS box cuts on thefemur using the cut guide surfaces of the femoral trial component. 4.The method of claim 3, wherein coupling the reamer bushing comprises:attaching a positioning ring to the attachment portion; and inserting areduced diameter portion of the reamer bushing into the positioningring.
 5. The method of claim 4, further comprising: preparing one ofmedial and lateral cuts through a corresponding one of medial andlateral cut slots defined in the femoral trial component for receipt ofa distal femoral augment.
 6. A method for preparing a femur forreceiving a prosthesis, the method comprising: fixing a femoral trialcomponent to the femur; coupling a reamer bushing relative to thefemoral trial component; reaming a cavity into the femur using thereamer bushing as a guide; coupling at least one of a modular femoralbox trial and a stem adapter relative to the femoral trial component;trialing the femoral trial component with the articulating surface ofthe femoral trial component by rotating the articulating surface againstan opposing bearing surface; and performing the coupling of the reamerbushing, the reaming of the cavity, the coupling of the at least one ofthe modular femoral box trial and the stem adapter, and the trialing ofthe femoral trial component all while the femoral trial componentremains fixed to the distal femur.
 7. The method of claim 6, furthercomprising positioning an intramedullary (IM) member in the femur. 8.The method of claim 6, further comprising positioning the femoral trialcomponent onto a distal end of the femur, the femoral trial componenthaving an attachment portion, an articulating surface, and at least twocut guide surfaces thereon.
 9. The method of claim 6, further comprisingselecting the reamer bushing from a plurality of reamer bushings, atleast one of the plurality of reamer bushings includes an offsetthroughbore.
 10. The method of claim 6, further comprising preparing PSbox cuts on the femur using cut guide surfaces of the femoral trialcomponent.
 11. The method of claim 10, wherein coupling the reamerbushing comprises: attaching a positioning ring to an attachment portionof the femoral trial component; and inserting a reduced diameter portionof the reamer bushing into the positioning ring.
 12. The method of claim11, further comprising preparing one of medial and lateral cuts througha corresponding one of medial and lateral cut slots defined in thefemoral trial component for receipt of a distal femoral augment.